Both players have performed instrumental roles during Gloucester's unbeaten start to the league campaign, with Richards orchestrating victory over Harlequins while Forrester starred in a high-scoring draw against Leicester last weekend.

Grayson is well aware of their possible combined effect as Saints target a Kingsholm triumph which could take them top.

"The big dangers against Gloucester are Peter Richards and James Forrester because they are allowed to run around the field and wreak havoc," said Northampton head coach Grayson.

"Gloucester do the basics very well, they have a strong front five and an aggressive back row, and they also have a string of talented, young backs with a bit of physicality.
"
With these players around them, it means Richards and Forrester can cause a lot of problems."

Saints are unchanged following their 33-18 victory over Bath last weekend, having closed the book on a difficult few days which saw a Rugby Football Union investigation into allegations that players from both sides traded racist abuse during the Franklin's Gardens clash.

Struggling Harlequins host their rugby director Dean Richards' former club Leicester on Saturday, having signed Craig McMullen as cover for injured fly-half Andrew Mehrtens.

Mehrtens faces a six-week absence while he recovers from a knee operation, and 33-year-old McMullen could go straight into the Quins squad.

Bath will be without captain Steve Borthwick against Recreation Ground visitors Worcester after he underwent knee surgery which could threaten his participation in England's autumn Tests.

And Worcester coach Anthony Eddy is quietly confident the Warriors can record a first Premiership win at the fourth attempt this season.

"It is a very hard task, but I believe we have a team that can beat Bath on their home ground," he said.

"They base a lot of their game on a strong and dominant set-piece similar to our own, and it will be a good challenge for both sets of forwards to see who gets on top."

Andy Farrell and Jason Robinson are set to oppose each other for the first time in their glittering rugby careers when champions Sale Sharks host Saracens on Friday night.

The former Wigan rugby league colleagues' potential clash comes less than a fortnight after Farrell made his union debut.

Farrell is retained on the Saracens bench following a successful 16-minute appearance against Newcastle last weekend, while Robinson captains a Sale side who have reeled off two straight Premiership wins after losing to Leicester earlier this month.

Saracens were the only club to lower Sale's colours on home soil last term, although they travel north without French star Thomas Castaignede, who suffered a recurrence of calf muscle trouble in training earlier this week.

Sale can keep in touch with early Premiership pace-setters Wasps and Bristol, who meet at the Memorial Stadium on Sunday, by sinking Saracens, and they are unchanged following a hard-fought win against Worcester last time out.

London Irish prop Neal Hatley will break Tony Diprose's record of 174 Premiership appearances when he runs out in a much-changed Exiles side at Newcastle on Friday night.

Exiles rugby director Brian Smith has further responded to a surprise 23-11 home defeat against Bristol six days ago by moving fly-half Riki Flutey into the centre alongside Mike Catt, while also calling up Barry Everitt and Michael Horak.